| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a tandem type image forming apparatus in which the problem of background fouling due to toner scattering in the conventional cloud development method is solved, thereby using a small particle size toner, and in which dot reproducibility which is a feature of non-contact development is further improved by using the small particle size toner. <P>SOLUTION: The tandem type image forming apparatus has, for each of color toners used for image formation: an electrostatic latent image bearing member; and a developing means in which a DC voltage and an AC voltage are superimposed and applied to an electrode for toner cloud generation disposed between a toner supply member and the electrostatic latent image bearing member in non-contact with these, whereby potential is applied to a toner supplied by the toner supply member to allow the toner to fly and an electrostatic latent image on the electrostatic latent image bearing member placed opposite to the toner supply member at an interval is developed with the toner. The toner has a weight average particle size (D4) of 2-7 μm, a D4 to Dn ratio (D4/Dn) of 1.0-1.2, a shape factor SF-1 of 110-150, and a shape factor SF-2 of 110-150, and value for F defined by F=q*(Vc+Vpp/2√2)/dc satisfies 50≤F≤300. <P>COPYRIGHT: (C)2010,JPO&INPIT |
